'We next wanted to demonstrate the utility of sRET in conditions where the acceptor and donor molecules were not covalently linked.'

'The iron - sulphur cluster associated with the Rieske centre of proteins normally functions in electron transfer reactions as it can act as an electron acceptor and donor.'

'They propose that the relatively low redox potential of hypericin permits it to compete as an electron acceptor, which consequently potentiates its biological activity in the dark, permitting it to interfere with the growth of tumors.'